The present invention relates to a syrup drink supply nozzle assembly installed in a drink dispenser or a cup drink vending machine for business use, to mix a syrup selected based on an instruction with cold water or carbonated water, and then to supply the mixture to a cup.
First, a drink dispenser such as that described above is taken as an example, with its drink system shown in FIG. 11. In this figure, numeral 1 is a drink dispenser, 2 is a drink supply nozzle provided in a vend stage 1a of the drink dispenser 1, 3 is a cooling-water bath built in the drink dispenser 1, 3a is an agitator for agitating the cooling water, 4 is a cooling unit for the cooling-water bath 3, 5 is a carbonator for producing carbonated water, 6 is a water supply pump connected to a water service pipe, 7A to 7D are syrup tanks for accommodating corresponding syrups of various flavors and colors, and 8 is a carbon-dioxide bomb.
Syrup lines 9, a carbonated-water line 10, and a cold-water line 11 are disposed between the drink supply nozzle 2 and each of the syrup tanks 7A to 7D, between the drink supply nozzle 2 and the carbonator 5, and between the drink supply nozzle 2 and the supply pump 6, respectively, via the cooling-water bath 3 of the drink dispenser 1. A cooling coil is interposed in each of the syrup lines 9A to 9D and cold water line 11 and immersed in water of the cooling-water bath 3, and the cold-water line 10 branches on its way to feed water to the carbonator 5 immersed in the cooling-water bath. Each line has corresponding syrup solenoid valves 12, carbonated-water solenoid valve 13, cold-water solenoid valve 14, and carbonator-water supply solenoid valve 15. In addition, pressurized carbon dioxide is supplied from the carbon-dioxide bomb 8 to each syrup tank 7A to 7D and the carbonator 5 through carbon-dioxide lines 16.
A drink dispenser of such a structure is well known. When an operator presses a drink selection button (not shown) with a cup 17 set on the vend stage 1a of the drink dispenser 1, a solenoid valve corresponding to the selected drink is opened according to an instruction from a control section in order to feed the drink supply nozzle 2 with the selected type of syrup and a diluent, that is, cold water (for a non-carbonated drink) or carbonated water (for a carbonated drink). The syrup and the diluent are mixed inside the nozzle and then ejected and supplied to the cup 17.
Next, FIG. 12 shows the construction proposed by the applicant in Japanese Patent Publication (KOKAI) No. 7-309398, as a conventional example of the drink supply nozzle 2 provided in the above drink dispenser. The syrup supply nozzle 2 is formed of an assembly of a nozzle head 2a and a cylindrical spout nozzle 2c installed on the outer periphery of the nozzle head 2a via an O-ring 2b. The nozzle head 2a has multiple syrup nozzles 2d formed therein so as to project downward from its tip and corresponding to the syrups, syrup introduction passages 2d-1 formed therein so as to lead to the corresponding syrup nozzles 2d, and a diluent passage 2e. The diluent passage 2e is formed of a combination of a vertical hole 2e-1 formed in the center of a top portion of the nozzle head 2a and horizontal holes 2e-2 radially branching from the terminal of a vertical hole 2e-1 and opened at a peripheral surface of the nozzle head. On the other hand, the spout nozzle 2c has a tip portion in the form of a circular arc, and has a drink ejection port 2c-1 formed in its center. In this drink supply nozzle 2, the syrup lines 9 corresponding to the various syrups as shown in FIG. 11 are connected to the inlets of the corresponding syrup introduction passages 2d-1 leading to the corresponding syrup nozzles 2d. In addition, the carbonated-water line 10 and the cold-water line 11 converge at the diluent passage 2e.
With such a construction, when a syrup drink is supplied, a syrup flowing from the syrup nozzle 2d and cold water or carbonated water ejected into the spout nozzle 2c through the diluent passage 2e are mixed together and then ejected from the drink ejection port 2c-l of the spout nozzle 2c toward the cup 17 (see FIG. 11) for supply.
In the conventional drink supply nozzle 2, the opening of the drink ejection port 2c-1 of the spout nozzle 2c is larger than the diameter of the circle enclosing all the syrup nozzles 2d so as to prevent the syrup dripping from the tip of the syrup nozzle 2d following the drink supply from adhering to an inner wall surface of the spout nozzle 2c, thereby preventing the syrup from mixing into the next drink sold. In addition, as shown in FIG. 13, the multiple syrup nozzles projecting from a lower end surface of the head 2a have their tips bent inward toward the center of the head 2a so that the locus of the syrup ejected from each syrup nozzle 2d generally passes the center of the drink ejection port 2c-1 formed in the tip of the spout nozzle 2c in order to prevent the syrup from adhering to the spout nozzle 2c, as is well known from Japanese Patent Publication (KOKAI) No. 10-72099.
Further, if carbonated water fed from the carbonator 5 following pressurization in the carbonated-gas bomb 8 as described in FIG. 12 is ejected, with its pressure maintained, into an inward space at the ambient atmospheric pressure in the spout nozzle 2c from the diluent passage 2e formed in the head 2a of the drink supply nozzle 2, the pressure then fluctuates rapidly to cause carbon dioxide dissolved in the carbonated water to substantially separate from water, thereby reducing the gas volume of the carbonated water to be mixed with the concentrated syrup. This degrades the quality of the carbonated drink. Thus, a pressure-reducing valve 18 is connected to a carbonated-water inlet extended from the drink supply nozzle 2 as shown in FIG. 12, so that the pressure of the carbonated water supplied from the carbonator through the carbon-dioxide line can be reduced to some degree before being introduced into the drink supply nozzle 2, as is well known from Japanese Patent Publication (KOKAI) No. 10-81398. The pressure-reducing valve 18 is structured so as to have a resistance piece 18a accommodated in a case 18b, and the resistance piece 18a has multiple pressure-reducing grooves formed on its outer peripheral surface, the grooves having an angular cross section.
The syrup drink supply nozzle assembly installed in a drink dispenser to selectively supply various syrup drinks of different flavors into a cup, as described above, is required to have the structures and functions specified below.
(a) Since the drink dispensers for business use in restaurants or the like must have their drink systems washed as a part of daily maintenance work for sanitation purposes, the drink supply nozzle has a structure that enables it to be simply disassembled and reassembled, and that can be washed easily by the user.
(b) In order to obtain high-quality drinks, a syrup and a diluent such as cold water or carbonated water supplied to the drink supply nozzle can be sufficiently mixed together inside the spout nozzle before the mixture is supplied to a cup, thereby allowing the diluent ejected into the spout nozzle to flow thoroughly and evenly over the entire periphery, without local mixture.
(c) In supplying a carbonated drink, the level of gas separation can be minimized while the carbonated water is passing through the drink supply nozzle, thereby maximizing the gas content in the carbonated water and enabling the supply of high-quality carbonated drink.
(d) During supply, drink is prevented from remaining in the spout nozzle due to the surface tension of the liquid, and thus flows out smoothly from the nozzle.
Analysis of the conventional drink supply nozzle 2 shown in FIG. 12 in view of the above points has revealed the following problems:
(1) When the multiple syrup nozzles 2d corresponding to various syrups, the syrup introduction passages 2d-1, and the diluent passage 2e are all formed in the unitary head 2a, the structure is complicated and manufacturing cost becomes high.
(2) Since the tip of the head 2a is flat and the syrup nozzles 2d are gathered to project therefrom toward the center of the head, syrup residue is likely to adhere to the flat tip surface of the head 2a and to remain thereon. In addition, this portion is difficult to clean due to the close arrangement of the syrup nozzles 2d.
(3) In addition, the diluent passage 2e formed in the head 2a by drilling is connected to a water service pipe via the cold-water line, so that a foreign material contained in city water may block the diluent passage inside the head. In such a case, it is also difficult to clean the inside of the diluent passage and to remove the foreign material from the passage. The pressure-reducing valve 18 connected to the carbonated water inlet of the drink supply nozzle 2 may similarly be blocked with a foreign material, and a large amount of time and labor is required to remove this foreign material due to the difficulty in disassembling the pressure-reducing valve.
(4) Despite the use of the pressure-reducing valve 18 connected to the inlet side of the drink supply nozzle 2 to reduce the pressure of supplied carbonated water, an amount of gas separated from the carbonated water increases due to repeated pressurization and pressure reduction during the flow through the subsequent diluent passage (bent into the form of an inverted "T") formed inside the nozzle. Consequently, high-quality carbonated drinks with a high gas content can not be obtained.
The results of various experiments on this point conducted by the inventor indicate that the optimal conditions for supplying high-quality carbonated water are those in which pressure reduction is carried out in the channel immediately before ejection into the spout nozzle, and in which rapid variation in pressure is not carried out within the diluent passage.
(5) When the diluent passage 2e formed in the head 2a is composed of holes that are dispersed in the peripheral surface of the head and are opened toward the spout nozzle 2c, the flow of the diluent is partially biased, thereby preventing the diluent from flowing uniformly over the entire inner peripheral surface of the spout nozzle 2c.
(6) The multiple syrup nozzles 2d are collectively arranged so as to face the center of the head in order to prevent syrup dripping from the nozzle from adhering to the spout nozzle 2c, so that syrup ejected from the syrup nozzle 2d and a diluent flowing down along the inner wall surface of the spout nozzle 2c may flow out from the drink ejection port 2c-1 toward the cup without being sufficiently mixed.
(7) When the cold-water line and the carbonated-water line converge on the diluent inlet of the head 2a, a pressure increase associated with drink remaining in the spout nozzle may cause carbonated water to flow backward into the cold-water line during the dispensing of a carbonated drink, whereas cold water may flow backward into the carbonated-water line during the dispensing of a non-carbonated drink. In particular, during the dispensing of a carbonated drink, the backward flow of carbonated water into the cold-water line may increase the loss of gas in the carbonated water.
(8) The remaining drink in the spout nozzle is the result of the surface tension of the liquid. In the conventional spout nozzle structure, however, the drink ejection port 2c-1 formed in the tip of the nozzle has a flat and continuous peripheral edge, whereby the surface tension of the liquid may contribute to occluding the drink ejection port 2c-1. Consequently, drink is likely to remain in the spout nozzle.
The present invention has been provided in view of the above points, and it is an object of the invention to solve each of the above problems in order to provide a syrup drink supply apparatus with improved maintenance ability in terms of parts washing or the like, as well as improved nozzle functions such as the mixing of a syrup and a diluent and maintenance of the gas content of carbonated water.